add sending mail for returned items

fet2020/rental/mails.py

@@ -78,3 +78,25 @@ def send_mail_rejected(obj):
         email.send()
     except Exception as exc:
         logger.info("Failed to send rejection email for rental #%s. Error: %s", obj.id, exc)
+
+
+def send_mail_returned(obj):
+    subject = f"FET-Verleih: {obj.get_status_display()}"
+
+    # Build email message
+    message = (
+        f"Hallo {obj.firstname},\n\n"
+        "deine Verleihgegenstände wurden erfolgreich zurückgegeben.\n\n"
+        "Liebe Grüße,\n"
+        "das Verleih-Team"
+    )
+
+    # Create email
+    email = EmailMessage(
+        subject, message, from_email=RENTAL_EMAIL, to=[obj.email], cc=[RENTAL_EMAIL]
+    )
+
+    try:
+        email.send()
+    except Exception as exc:
+        logger.info("Failed to send returned email for rental #%s. Error: %s", obj.id, exc)

fet2020/rental/models.py

@@ -2,7 +2,7 @@ from django.core.validators import FileExtensionValidator
 from django.db import models
 from django.forms import ValidationError
 
-from .mails import send_mail_approved, send_mail_rejected
+from .mails import send_mail_approved, send_mail_rejected, send_mail_returned
 from .managers import RentalItemsManager
 from .validators import PhoneNumberValidator
 
@@ -104,6 +104,12 @@ class Rental(models.Model):
             and self.status == self.Status.REJECTED
         ):
             send_mail_rejected(self)
+        elif (
+            pre_obj
+            and pre_obj.status != self.Status.RETURNED
+            and self.status == self.Status.RETURNED
+        ):
+            send_mail_returned(self)
 
     def clean(self):
         if not self.date_end: